1. Field of the Invention
This invention relates generally to thermal blankets and, more particularly, to thermal blankets that deliver a bath of a thermally-controlled medium to a body.
2. Description of the Related Art
It often is necessary to bathe a patient in a thermally-controlled medium for the purpose of controlling the patient's body temperature. For example, it is important to keep a patient warm during surgery and to warm the patient post-operatively to reduce the risk of hypothermia. Typically, a patient's body temperature is controlled during surgery by using operating room blankets that cover the parts of a patient's body not being operated upon. Multiple blankets are overlaid, or variously shaped blankets having cut-outs or flaps are used, to cover most of the patient and still provide access to target surgical sites. After surgery, the patient is covered with a full-body blanket that covers all of the patient except for the head. Thus, as much of the patient as possible is kept covered during surgery to keep the patient warm while providing access to the operating site and after surgery a full body blanket keeps the patient warm.
It is known to provide an inflatable covering into which a thermally-controlled inflating medium is introduced. For warming purposes, the inflating medium can be warmed air. The thermally controlled medium also can be cooled air. When such a covering is inflated, it self-erects about a patient to produce a structure having a thermally-controlled interior environment. See, for example, U.S. Pat. Nos. 4,572,188 and 5,324,320, commonly assigned with this application and incorporated herein by this reference.
The prior art inflatable covering is an inflatable blanket that includes an array of apertures on its underside. The thermally-controlled medium is exhausted from the apertures into the erected structure and bathes the patient in the inflating medium. The temperature of the environment provided by the inflated blanket is determined by the temperature of the inflating medium. Thus, relatively uniform and precise control over the ambient environment of the patient can be achieved. Such thermal blankets are advantageously used to warm or cool patients before, during, and after surgery.
To expose an operating site during surgery or otherwise permit access to part of a patient's body while using an inflatable thermal blanket, a patient is covered with the blanket and a blanket area around the site of interest is sealed to provide a boundary against deflation. The blanket within the sealed area can be cut out, creating an open space in the blanket for access to the site of interest, while maintaining the inflatable integrity of the blanket. The blanket can then be inflated with the thermally-controlled medium to completely cover the patient except for the site of interest and thereby control the patient's temperature during surgery. After surgery, the inflatable blanket can be removed and replaced with a full-body blanket or a supplemental blanket can be draped across the exposed site. See, for example, U.S. patent application Ser. No. 07/638,748, commonly assigned with this application and incorporated herein by this reference.
It would be advantageous if it were not necessary to change blankets or add blankets between surgery or other medical procedures and the recovery period. This would permit a single blanket to be used for each patient, rather than multiple blankets. A single blanket would make it unnecessary to layer multiple blankets or to cut or shape blankets to provide surgical access to parts of a patient's body. The cost of maintaining an inventory of blankets and the time spent changing or modifying blankets also could be saved.
From the discussion above, it should be apparent that there is a need for a thermal blanket that can be used to cover a patient during surgery or other medical procedures in which it is necessary to gain access to a portion of the patient's body and that also can be used after the medical procedure is completed to fully cover the patient and provide a thermally-controlled environment. The present invention satisfies this need.